:MEASure:EYE:CTDecq

Flex Apps:

FlexDCA

Meas. mode:

Eye

Waveform type:

PAM4

Command Syntax

:MEASure:EYE:CTDecq

Query Syntax

:MEASure:EYE:CTDecq?

Description

The CER TDECQ (Codeword Error Ratio Transmitter and Dispersion Eye Closure Quaternary) measurement is a power penalty measurement of a PAM4 optical transmitter's quality. It differs from a TDECQ measurement in that it is based on a codeword error ratio rather than a symbol error ratio. Use a TDECQ Equalizer function (:FUNCtion1:FOPerator TEQualizer) when making a compliance measurement.

You can configure the CER Codeword definitions and Target CER error rate for this measurement using these commands:

This measurement does not support PAM6 or PAM8 waveforms.

Measurement Identification

Avoid subtle programming errors! To ensure that the correct measurement is installed or queried, always explicitly identify a measurement when installing a measurement or querying a measured value, status, or detail. To identify a measurement, specify the measurement's source waveform (:SOURce child command). With some measurements, you may also need to specify other identifying values. Generally, when selecting a measurement using FlexDCA's GUI, if a dialog appears prompting you to select values, you should explicitly specify these values when remotely identifying the measurement. More information.

For example, to return the status of the measurement, :MEASure:EYE:CTDecq

flex.write(':MEASure:EYE:CTDecq:SOURce CHAN1A')
if flex.query(':MEASure:EYE:CTDecq:STATus?') == 'CORR';
    measurement = flex.query(':MEASure:EYE:CTDecq?')
else:
	details = flex.query(':MEASure:EYE:CTDecq:STATus:DETails?')
	reason = flex.query(':MEASure:EYE:CTDecq:STATus:REASon?')

Measurement Ready?

To confirm that the measurement is ready to read, you can query the measurement's status:

if ('CORR' in Flex.query(':MEASure:EYE:CTDecq:STATus?')):
	measurement = Flex.query(':MEASure:EYE:CTDecq?')

If averaging is turned on (:ACQuire:AVERaging), you can also confirm if the measurement result is ready by comparing the number of specified averages (:ACQuire:ECOunt?) versus the number of measurement sweeps that have occurred (:MEASure:EYE:CTDecq:COUNt?). The technique uses the :COUNt? common measurement query. For example,

if (Flex.query(':MEASure:EYE:CTDecq:COUNt?') >= Flex.query(':ACQuire:ECOUNt?')):
	measurement = Flex.query(':MEASure:EYE:CTDecq?')

You can also use an acquisition limit lest to test that a number of waveform samples, or pattern acquisitions have completed before returning a measurement. Refer to the :LTESt:ACQuire:CTYPe command.

Common Measurement Child Queries

This command supports the use of the following common measurement queries: :LOCation?, :COUNt?, :MAXimum?, :MINimum?, :MEAN?, and :SDEViation?.

Requires FlexDCA revision A.08.30 and above.